As a technique to measure the concentration of a substance contained in an organism-derived sample such as blood and urine, an electrochemical technique that detects a signal related to an electron exchange between a target substance and a working electrode is known. As an electrochemical technique, an electrochemical sensor using a technique (amperometric method) of detecting a current generated between the working electrode and a counter electrode when, for example, the target substance is oxidized or reduced on the working electrode is disclosed. As such a sensor, for example, a glucose sensor that measures the concentration of glucose based on a current response obtained by oxidizing hydrogen peroxide using generated hydrogen peroxide when glucose is oxidized by glucose oxidase is known. Hereinafter, the present invention will be described based on the amperometric method, but the application of the present invention is not limited to the amperometric method and the present invention can be applied to any method of detecting a response when a voltage is applied to the working electrode.
To analyze an organism-derived sample highly sensitively by applying an electrochemical technique, it is necessary to curb the influence of a large amount of coexisting components contained in the organism-derived sample on a detection reaction. PTL 1 describes a method of using magnetic particles as an example of the method of selectively separating a component to be analyzed from coexisting components by an analyzer using the amperometric method.